High pressure relief valve spring assembly

ABSTRACT

In one featured embodiment, a spring assembly for a valve comprises a spring, a spring seat including a cup-shaped portion for seating one end of the spring, and a ball received within a recess formed within the cup-shaped portion of the spring seat. The ball is defined by a ball diameter. A disc prevents the ball from contacting a piston. The disc is defined by an outer diameter and includes a center opening defined by an inner diameter. A ratio of the inner diameter to the ball diameter is between 0.60 and 0.65.

BACKGROUND OF THE INVENTION

This application relates to a high pressure relief valve which may beutilized in a fuel control for an aircraft engine.

A fuel system provides fuel to various portions of a gas turbine engine.The fuel system includes a fuel pump and a High Pressure Relief Valve(HPRV) that supplies fuel to the gas turbine engine.

Should the fuel system experience a blockage, pressure will build up inthe system. The HPRV allows fuel pressure to be relieved from a locationdownstream of the pump, with the fuel then being returned to a pumpinlet. The HPRV is essential to safe operation of a fuel pumping unitand is designed to relieve excessive pressure and prevent catastrophicfailure of the fuel pump and main housing. The existing high pressurerelief valves may sometimes result in undesirably high pressure losses.

Performance of the HPRV is critical to seamless operation of the fueldelivery system.

SUMMARY OF THE INVENTION

In one exemplary embodiment, a spring assembly for a valve comprises aspring, a spring seat including a cup-shaped portion for seating one endof the spring, and a ball received within a recess formed within thecup-shaped portion of the spring seat. The ball is defined by a balldiameter. A disc prevents the ball from contacting a piston. The disc isdefined by an outer diameter and includes a center opening defined by aninner diameter. A ratio of the inner diameter to the ball diameter isbetween 0.60 and 0.65.

In another exemplary embodiment, the recess of the cup-shaped portion isdefined by a recess inner diameter and wherein a ratio of the recessinner diameter to the ball diameter is between 1.01 and 1.10.

In another exemplary embodiment, the cup-shaped portion is defined by anouter diameter and by a length, and wherein a ratio of the outerdiameter of the cup-shaped portion to the length of the cup-shapedportion is between 4 and 5.

In another exemplary embodiment, a high pressure relief valve comprisesa valve housing defining an internal bore and having a valve inletconfigured to be in fluid communication with a pump outlet. A closuresleeve is at least partially received within the internal bore, andcomprises a sleeve body surrounding a center axis. The sleeve body hasan internal cavity that is enclosed at the downstream end and is open atthe upstream end. A piston is received within the internal cavity, andthe internal cavity is defined in part by a piston contact surface thatis defined by an inner diameter. The piston includes an outer surfacedefined by a maximum outer piston diameter and a piston bore that isdefined by a piston inner diameter. The piston contact surface slidesagainst the outer surface of the piston. A nozzle is received within theinternal bore of the valve housing and includes a nozzle bore having anozzle inlet in fluid communication with the valve inlet and a nozzleoutlet. A spring assembly biases the piston to close the nozzle outlet.The spring assembly includes a spring, a spring seat including acup-shaped portion for seating one end of the spring, a ball receivedwithin a recess formed within the cup-shaped portion of the spring seat,and a disc that prevents the ball from contacting the piston. When asystem pressure at the nozzle outlet exceeds a predetermined pressurelevel, a spring biasing load is overcome to open the nozzle outlet tofluidly connect the nozzle to the internal cavity of the closure sleeve.The high pressure relief valve includes one or more of the followingvalve characteristics: wherein the ball is defined by a ball diameterand wherein the disc is defined by an outer diameter and includes acenter opening defined by an inner diameter, and wherein a ratio of theinner diameter to the ball diameter is between 0.60 and 0.65; whereinthe disc is defined by a thickness extending from an upstream side ofthe disc to a downstream side of the disc, and wherein a ratio of thethickness of the disc to the outer diameter of the disc is between 0.06and 0.08; wherein the recess formed within the cup-shaped portion of thespring seat is defined by a recess inner diameter and wherein a ratio ofthe recess inner diameter to the ball diameter is between 1.01 and 1.10;wherein the spring is defined by an inner diameter, and wherein thecup-shaped portion is defined by an outer diameter, and wherein a ratioof the outer diameter of the cup-shaped portion to the inner diameter ofthe spring is between 0.90 and 0.98; wherein the cup-shaped portion isdefined by an outer diameter and by a length, and wherein a ratio of theouter diameter of the cup-shaped portion to the length of the cup-shapedportion is between 4 and 5; wherein the disc is defined by an outerdiameter, and wherein a ratio of the outer diameter of the disc to thepiston inner diameter is between 0.97 and 0.99; wherein the spring seatis defined by a maximum outer diameter, and wherein a ratio of themaximum outer diameter of the spring seat to the piston inner diameteris between 0.8 and 0.9.

These and other features may be best understood from the followingdrawings and specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of a fuel system for an aircraft.

FIG. 2 is a cross-sectional view of the high pressure relief valve ofFIG. 1.

FIG. 3 a perspective view of the closure sleeve and nozzle from the highpressure relief valve of FIG. 2.

FIG. 4 is an assembled view for the components of FIG. 3.

FIG. 5 is a section view through the closure sleeve.

FIG. 6 is a side view of the closure sleeve.

FIG. 7 is a section view through the nozzle of FIG. 3.

FIG. 8 is a magnified view of a nozzle face as identified in FIG. 7.

FIG. 9 is a section view through a piston of the high pressure reliefvalve of FIG. 2.

FIG. 10 is a perspective view of the piston.

FIG. 11 is a section view of a spring seat of a spring assembly as shownin FIG. 2.

FIG. 12 is a perspective view of the spring seat of FIG. 11.

FIG. 13 is a section view of a disc of a spring assembly as shown inFIG. 2.

FIG. 14 is an end view of the disc of FIG. 13.

DETAILED DESCRIPTION

FIG. 1 shows a schematic view of an aircraft fuel supply system 20having a fuel pump 22 drawing fuel from a fuel supply 24. The pump 22has a pump inlet 26 in fluid communication with the fuel supply 24 and apump outlet 28 is in fluid communication with a high pressure reliefvalve (HPRV) 30. During normal operating conditions the HPRV 30 remainsclosed and the fuel passes through a filter to remove contaminants. Fuelexiting the filter is then directed to fuel metering system 32 with afuel metering valve 34 to supply fuel to an engine 36. If the supply offuel at the fuel metering system 32 is excessive for the current engineoperating condition the excess fuel is ported back to the pump inlet 26.

The HPRV 30 is positioned immediately downstream of the pump outlet 28.Should the system 20 become clogged or blocked, the pressure will becomeundesirably high, which could result in damage to the pump 22 or pumphousing 36. The HPRV 30 will automatically open once a specifiedpressure level is exceeded to allow fuel to return to the pump inlet 26.

A cross-sectional view of the HPRV 30 is shown in FIG. 2. The HPRV 30 iscomprised of a valve housing 40 aligned longitudinally along a valvecenter axis A, a closure sleeve 42 received within the valve housing 40,a piston 44 received within the closure sleeve 42, a nozzle 46, and aspring assembly 48 that biases the HPRV 30 to the closed position. Thespring assembly 48 includes a spring 50, a spring seat 52, a ball 54,and a washer or disc 56. A half ball 58 is positioned axially betweenone end of the piston 44 and the nozzle 46.

The closure sleeve 42 and nozzle 46 are shown in greater detail in FIGS.3-5. The closure sleeve 42 comprises a one-piece component that isconfigured to include a HPRV assembly with the HPRV 30 while alsoproviding an end cap closure. This configuration reduces the overallnumber of components for the HPRV 30.

As shown in FIG. 3, the closure sleeve 42 has an upstream end 60 and adownstream end 62. The upstream end 60 is received within an internalbore or cavity 64 (FIG. 2) of the valve housing 40 and the downstreamend 62 extends outwardly of the valve housing 40. The closure sleeve 42defines an internal cavity 66 (FIG. 5) within which the spring assembly48 and piston 44 are received. The downstream end 62 of the closuresleeve 42 is enclosed such that when the closure sleeve 42 is mountedwithin the valve housing 40, the HPRV 30 is sealed. As shown in FIG. 2,a seal 68 is positioned radially between an inner surface 70 of thevalve housing 40 and an outer surface 72 of the closure sleeve 42 at adownstream end 74 of the valve housing 40 to ensure that the internalcavities 64, 66 are sealed from leaking externally.

As shown in FIG. 5, the internal cavity 66 is defined in part by aninner surface 76 that directly abuts against an outer surface 78 of thepiston 44 in a sliding relationship. The inner surface 76 of the closuresleeve 42 is defined by an inner diameter ID_(C) and a piston engagementsleeve length L₁ (FIG. 5). The outer surface 78 of the piston 44 isdefined by an outer diameter OD_(P) (FIG. 9). The outer diameter OD_(P)comprises the maximum outer diameter of the piston 44. As shown in FIG.5, the flange 80 extends radially outwardly of the closure sleeve 42,which abuts against the downstream end 74 of the valve housing 40 (FIG.2). A notch or groove 82 is formed within the outer surface of theclosure sleeve 42 immediately upstream of the flange 80. The seal 68(FIG. 1) is received within the groove 82.

The closure sleeve 42 includes one or more vent or damping orifices 84(FIG. 6) that extend through a thickness of the closure sleeve 42 fromthe inner surface to the outer surface of closure sleeve 42. The dampingorifice 84 is defined by a diameter D_(D). The damping orifice 84 is influid communication with an annulus 86 (FIG. 2) that is formed radiallybetween the closure sleeve 42 and the valve housing 40. The annulus 86is in fluid communication with a separate pressure input P_(I). Thedamping orifice 84 facilitates slowing down, i.e. controlling how fastthe valve can move. A seal 88 (FIG. 2) is positioned radially betweenthe valve housing 40 and the closure sleeve 42. The seal 88 is seatedwithin a notch 89 (FIG. 5) formed within the closure sleeve 42. Thisseal 88 allows the pressure input P_(I) to be independent of thepressure outlet P_(d). The internal cavity 66 of the closure sleeve 42comprises a spring cavity that receives the spring assembly 48. Pressurewithin the spring cavity is the same as the pressure input P_(I).

The closure sleeve 42 includes a plurality of windows 90 (FIG. 3) thatare circumferentially spaced apart from each other about the closuresleeve 42 adjacent the upstream end 60. Each window 90 is defined by awindow diameter D_(w) (FIG. 5). The windows 90 are in fluidcommunication with the internal cavity 64 (FIG. 2) of the valve housing40 at the pressure outlet Pd. Once system pressure P_(S) is greater thanthe biasing force of the spring assembly 48 (spring load) plus thespring cavity pressure, the half ball 58 is unseated from the nozzle 46and the spring assembly 48 moves to the left, i.e. downstream, whichallows fluid to flow through the windows 90 and exit the pressure outletP_(d). The exiting fluid is then returned to the pump inlet 26.

The closure sleeve 42 also includes a pair of slots 92 (FIG. 3) formedin the upstream end 60. In one example, the slots 92 are spaced onehundred and eighty degrees apart from each other. The slots 92 aredefined by a slot width S_(W) and a slot depth or length S_(L) (FIGS.5-6). The slots 92 receive corresponding tabs 94 (FIGS. 3 and 7) thatare on the nozzle 46 as best shown in FIG. 4. After the tabs 94 areinserted into the slots 92 a snap ring 96 fits in a groove 98 in theclosure sleeve 42 to prevent the closure sleeve 42 and nozzle 46 fromseparating from each other. The snap ring 96 is shown positionedexternally on the closure sleeve 42 for this configuration; however, itcan also be incorporated on an inner diameter ID of the closure sleeve42 to achieve the same retention of the nozzle 46.

The inner diameter that defines the internal cavity 66 of the closuresleeve 42 is sized to accommodate the HPRV spring assembly 48. The outerdiameter that defines the outer surface of the closure sleeve 42 issized, relative to the bore (internal cavity 64) of the valve housing40, to minimize pressure drop in the bore of the valve housing 40. Theclosure sleeve 42, thus, optimizes flow through the HPRV 30 while alsoproviding containment of valve components in a cartridge type design.The windows 90 are configured to minimize pressure drop through the HPRV30 while regulating the pressure acting on the piston 44. The windowsare also positioned to minimize hydraulic side loading of the piston 44.

In one embodiment, the inner diameter ID_(C) of the closure sleeve 42 atthe engagement surface with the piston 44 is 1.0 inches (2.54centimeters) and the interface length L₁ of the closure sleeve 42 is 1.3inches (3.30 centimeters). In embodiments, a ratio of the interfacelength L₁ to the inner diameter ID_(C) is between 1.0 and 1.5.

In one embodiment, the closure sleeve 42 has a slot width S_(W) of 0.4inches (1.02 centimeters) and the inner diameter ID_(C) is 1.0 inches(2.54 centimeters). In embodiments, a ratio of the slot width S_(W) tothe inner diameter ID_(C) is between 0.1 and 0.6.

The slot length S_(L) is 0.25 inches (0.635 cm) and a slot width S_(W)is 0.4 inches (1.02 centimeters). A ratio of slot width S_(W) to slotlength S_(L) is between 1.0 and 2.5. In one embodiment, the windowdiameter D_(W) is 0.35 inches (0.89 centimeters) and the outer diameterOD_(P) of the piston 44 at the engagement surface to the sleeve 42 is1.0 inches (2.54 centimeters). In embodiments, a ratio of the windowdiameter D_(W) to the outer diameter OD_(P) of the piston 44 is between0.3 and 0.5.

In one embodiment, the diameter D_(D) of damping orifice 84 is 0.032inches (0.08 centimeters) and the inner diameter ID_(C) is 1.0 inches(2.54 centimeters). In embodiments, a ratio of the diameter D_(D) of thedamping orifice 84 to the inner diameter ID_(C) is between 0.020 and0.050.

In one embodiment, a length L_(x) from a center of the windows 90 to adepth face 100 of the slot 92 is within the range of 0.09 inches (0.23centimeters) to 0.44 inches (1.12 centimeters).

The nozzle 46 is shown in greater detail in FIGS. 3-4 and 7. The nozzle46 controls the inlet flow and balances momentum forces against thespring load. The nozzle 46 includes a nozzle bore 101 (FIG. 7) thatextends from an inlet end 102 to an outlet end 104. The nozzle 46 isdefined by an overall nozzle length L_(N) that extends from the inletend 102 to the outlet end 104. The inlet end 102 is in fluidcommunication with an inlet bore 103 (FIG. 2) of the valve housing 40that receives fluid at the system pressure P_(S).

The nozzle 46 is defined by an outer surface 106 that extends from theinlet end 102 to an upstream side of the tabs 94. This outer surface 106is defined by a generally constant nozzle outer diameter OD_(N). Thetabs 94 are defined by a tab outer diameter that is greater than thenozzle outer diameter OD_(N). The nozzle 46 also includes a taperingouter surface portion 108 that extends from a downstream side of thetabs 94 to the outlet end 104.

The outlet end 104 provides an outlet end face 110 (FIG. 8), i.e. nozzleface, that is defined by an outlet outer diameter OD_(O) and an outletinner diameter ID_(O) that are radially spaced apart from each other bya radial distance R_(N1) (FIG. 8) to define an annular thickness at theoutlet end face 110. The annular outlet end face 110 contacts agenerally flat end face 112 of the half ball 58 when the HPRV 30 is inthe closed position.

The inlet end 102 of the nozzle 46 provides an inlet end face 114 (FIG.7) that is defined by an inlet outer diameter OD_(I) and an inlet innerdiameter ID_(I) that are radially spaced apart from each other by aradial distance R_(N2) to define an annular inlet end face 114. Theinlet inner diameter ID_(I) is greater than an inner diameter D_(H) ofthe valve housing 40 at the inlet bore 103. This configuration preventspressure loss at this location.

The outer surface 106 of the nozzle 46 includes a groove 116 thatreceives a seal with slipper 118 (FIG. 2). This seal is provides sealingbetween the valve housing 40 and the nozzle 46.

The nozzle bore 101 includes at least a first bore section B1 (FIG. 7)and a second portion section B₂. The first bore section B₁ is defined bya generally constant diameter (corresponding to the outlet innerdiameter ID_(O)) that extends along a first bore section length L_(B1).The first bore section length L_(B1) extends from the outlet end face110 to a position 120 within the nozzle bore 101. In one example, theposition 120 is located upstream of the tabs 94.

The second bore section B₂ comprises a conical section that has avariable diameter. The second bore section B₂ is defined by a secondbore section length L_(B2) that extends from the position 120 to theinlet end face 114. The second bore section B₂ has a smallest diameter(corresponding to the outlet inner diameter ID_(O)) at the position 120and a largest diameter (corresponding to the inlet inner diameterID_(I)) at the inlet end face 114. The second bore section B₂ increasesin diameter in a generally constant manner from the position 120 to theinlet end face 114 such that the second bore section is defined by aconical surface angle A_(N).

In one embodiment, at the nozzle face, i.e. the outlet end face 110, thenozzle 46 has an outlet inner diameter ID_(O) that is 0.280 inches(0.711 centimeters) and an outlet outer diameter OD_(O) that is 0.297inches (0.754 centimeters). In embodiments, a ratio of the outlet innerdiameter ID_(O) to the outlet outer diameter OD_(O) is between 0.95 and0.98.

In one embodiment, the outlet inner diameter ID_(O) is 0.280 inches(0.711 centimeters) and the first bore section length L_(B1) is 0.290inches (0.737 centimeters). The ratio of the outlet inner diameterID_(O) at the nozzle face to the first bore section length L_(B1) isbetween 0.80 and 1.10.

In one embodiment, the outlet inner diameter ID_(O) is 0.280 inches(0.711 centimeters) and the overall nozzle length L_(N) is 1.055 inches(2.680 centimeters). The ratio of the outlet inner diameter ID_(O) atthe nozzle face to the overall nozzle length L_(N) is between 0.30 and0.25.

In one embodiment, the conical surface angle A_(N) of the nozzle 46 iswithin a range between 0 degrees and 25 degrees.

The nozzle 46 is sized to handle the required flow while meeting systemrequirements for performance. The nozzle 46 is configured to reducepressure drop, off-centered flow, and flow swirling. The larger diameterat the inlet to the nozzle is sized to align with the valve housinginlet plumbing line. The smaller nozzle diameter is sized to balancemomentum loads to minimize valve droop. The nozzle length is sized toallow a 20 degrees transition “cone” from the plumb line inlet diameterto the smaller nozzle outlet diameter. In one example, the smallernozzle diameter, i.e. the outlet inner diameter ID_(O), is sized tomaintain a diameter to length ratio of 1.0.

The piston 44 is shown in greater detail in FIGS. 9-10. The piston 44comprises a cylindrical body portion 130 with an upstream end 132 and adownstream end 134. A piston bore 136 is formed within the cylindricalbody portion 130 to receive the spring assembly 48 (FIG. 2). The bore isdefined by an inner diameter ID_(P). A boss portion 138 is formed at theupstream end 132 to serve as a seat for the half ball 58 (FIG. 2). Theboss portion 138 encloses one end of the piston bore 136 leaving theopposite end open to receive the spring assembly 48.

The piston 44 has a maximum outer diameter OD_(P) which forms the outersurface 78 that abuts against the closure sleeve 42. One portion of thisabutment surface 78 is formed at the downstream end 134 and anotherportion of this abutment surface 78 is formed at the upstream end 132.These two portions are axially separated from each other by an undercutportion having an outer surface 140 that is defined by an outer diameterOD_(R) that is less than the maximum outer diameter OD_(P). This outersurface 140 is spaced radially inwardly of an inner surface of theclosure sleeve 42 to form an annulus 142 between the sleeve 42 andpiston 44 (FIG. 2).

One or more vent windows 144 (FIG. 9) are formed within the piston 44.The vent windows are defined by a vent diameter D_(V) and extend througha thickness of the piston 44 from the outer surface 140 to the pistonbore 136. The vent windows 144 fluidly connect the spring cavity 66 withthe annulus 142 (FIG. 2). The annulus 142 is in fluid communication withthe damping orifice 84 formed in the closure sleeve 42, which is influid communication with the annulus 86. The vent windows 144 are sizedbased on the size of the damping orifice 84 in the closure sleeve 42.The vent windows 144, annulus 142, damping orifice 84, and annulus 86cooperate with each other to control movement of the valve to reducepressure losses.

The piston 44 is defined by an overall length L_(P), the cylindricalbody portion 130 is defined by a length L_(E), and the boss portion 138is defined by a length L_(B). The boss portion 138 includes a conicalopening 146 (FIG. 9) that is defined by a conical surface 148 thatserves as a seat for the half ball 58. The conical surface 148 isdefined by a conical angle α_(c). The depth of the conical opening 146from the apex of the conical surface 148 to the end face of the bossportion 138 is defined by a length L_(C).

As shown in FIG. 2, the half ball 58 is semi-hemispherical in shape andhas a substantially flat surface 112 that faces the nozzle 46 and aspherical surface 150 that sits in the conical opening 146. Thespherical surface 150 cooperates with the conical surface 148 to allowpivoting movement of the hall ball 58 such that the nozzle face can befully sealed in the closed position even if the piston and nozzle arenot fully in axial alignment with each other.

In one embodiment, the length L_(E) of the cylindrical body portion 130that includes the outer surface portions 78, 140 is 1.13 (2.870centimeters) and the maximum outer diameter OD_(P) is 1.00 inches (2.54centimeters). The ratio of the length L_(E) of the cylindrical bodyportion 130 to the maximum outer diameter OD_(P) is between 1.0 and 1.2.

In one embodiment, the damping orifice diameter D_(D) in the closuresleeve 42 is 0.032 (0.081 centimeters) and the vent window diameterD_(V) is 0.078 inches (0.198 centimeters). The ratio of the dampingorifice diameter D_(D) to the vent window diameter D_(V) is between0.375 and 0.45.

In one embodiment, the outer diameter OD_(R) of the undercut portionhaving surface 140 is 0.954 inches (2.423 centimeters) and the maximumouter diameter OD_(P) is 1.0 inches (2.54 centimeters). The ratio of theouter diameter OD_(R) of the undercut portion having the surface 140 tothe maximum outer diameter OD_(P) is between 0.8 and 1.0.

In one embodiment, the conical angle α_(c) of the boss portion 138 iswithin a range of between 100 degrees and 120 degrees.

In one embodiment, the depth or length L_(C) of the conical opening 146in the boss portion 138 is 0.277 inches (0.704 centimeters) and themaximum diameter OD_(C) of the boss portion 138 with the conical opening146 is 0.850 inches (2.159 centimeters). The ratio of the length L_(C)of the conical opening 146 to the maximum diameter OD_(C) of the bossportion 138 is between 0.3 and 0.4.

As shown in FIG. 2, the piston 44 provides the conical seat for the halfball 58 as well as the pressure area internal to the closure sleeve 42.The seat is sized to hold the half ball 58 and allows for ball rotation.The piston maximum outer diameter OD_(P) (FIG. 9) is sized for apressure area to meet valve performance requirements. The internalannulus is sized to provide a ten times area increase over the springcavity damping orifice 84. The vent windows 144 in the piston 44 aresized to a ten times area increase over the spring cavity dampingorifice 84. The number of windows is optimized to vent air in anyorientation of the piston 44.

As discussed above, the spring assembly 48 (FIG. 2) includes the springseat 52, the ball 54, the disc 56, and the spring 50. The spring seat 52is shown in greater detail in FIGS. 11-12 and the disc 56 is shown ingreater detail in FIGS. 13 and 14. The spring seat 52 comprises acup-shaped body 160 with a recess 162 for seating the ball 54. Therecess 162 is defined by a maximum inner diameter ID_(M). The ball 54 isdefined by a ball diameter D (FIG. 1). The base of the cup-shaped body160 has an opening 164 into the piston bore 136, and thus is fluidlyconnected to the spring cavity 66. The cup-shaped portion 160 is definedby a maximum outer cup diameter D_(C) and a length L_(S). The opening164 facilitates seating of the ball 54 within the cup-shaped portion160.

The spring seat 52 fits within the piston bore 136. The spring seat 52includes an enlarged flange portion 166 with an outer edge 168 thatslides against an inner surface of the piston bore 136. The outer edge168 is defined by a maximum outer diameter OD_(M) of the spring seat 52.

As shown in FIGS. 13-14, the disc 56 has a thickness T that extends froman upstream side 170 to a downstream side 172 of the disc 56. The disc56 is defined by an outer diameter OD and has a center opening 174 thatis defined by an inner diameter ID.

In one example, the piston 44 is made from an aluminum material whilethe ball 54 is comprised of a steel material. The disc 56 is alsocomprised of a steel material. The disc 56 is tightly fit within thepiston 44 and is positioned axially between an end face of the pistonbore 136 and the ball 54 to keep the ball 54 from contacting the piston44.

As shown in FIG. 2, the spring 50 has a first end 178 that is seatedagainst an end face of the closure sleeve 42 and a second end 180 thatis seated against the flange portion 166 of the seat 52. The spring end180 surrounds the cup-shaped portion 160. The spring 50 is defined by aspring inner diameter IS and a coil diameter C. As known, springs do notalways push in a completely straight line. The ball 54 allows the springseat 52 to rotate around the ball by approximately 8 degrees until theupper or lower edge 168 of the flange portion 166 contacts the disc 56.

In one example, the outer diameter OD of the disc 56 is 0.837 inches(2.126 centimeters) and the inner diameter ID_(P) of the piston 44 is0.85 inches (2.159 centimeters). The ratio of the outer diameter OD ofthe disc 56 to the inner diameter ID_(P) of the piston 44 is between0.97 and 0.99.

In one example, the inner diameter ID of the disc 56 is 0.192 inches(0.488 centimeters) and the diameter D of the ball 54 is 0.312 inches(0.792 centimeters). The ratio of the inner diameter ID of the disc 56to the diameter D of the ball 54 is between 0.60 and 0.95.

In one example, the thickness T of the disc 56 is 0.06 inches (0.152centimeters) and the outer diameter OD of the disc 56 is 0.837 inches(2.126 centimeters). The ratio of the thickness T of the disc 56 to theouter diameter OD of the disc 56 is between 0.06 and 0.08.

In one example, the inner diameter ID_(M) of the spring seat 52 is 0.316inches (0.803 centimeters) and the diameter D of the ball 54 is 0.312inches (0.792 centimeters). The ratio of inner diameter ID_(M) of thespring seat 52 to the diameter D of the ball 54 is between 1.01 and1.10.

In one example, the maximum outer diameter OD_(M) of the spring seat 52is 0.710 inches (1.803 centimeters) and the inner diameter ID_(P) of thepiston 44 is 0.85 inches (2.159 centimeters). The ratio of maximum outerdiameter OD_(M) of the spring seat 52 to the inner diameter ID_(P) ofthe piston 44 is between 0.8 and 0.9.

In one example, the maximum axial distance between the seat 52 and thedisc 56 (FIG. 2) is approximately two times the nominal spacing betweenthe seat 52 and the disc 56. The nominal spacing is shown in FIG. 2 asthe axial distance between the seat 52 and disc 56 when both componentsare aligned with each other. If the upper or lower edge 168 of the seat52 contacts the disc 56. The furthest distance, i.e. the maximum axialdistance, at the non-contacting edge 168 is no more than two times thenominal spacing.

In one example, the maximum length L_(S) of the cup-shaped portion 160is 60-100% of a coil diameter of the spring 50.

In one example, the outer diameter Dc of the cup-shaped portion 160 is0.439 inches (1.115 centimeters) and the inner diameter IS of the spring50 is 0.459 inches (1.166 centimeters). The ratio of outer diameter Dcof the cup-shaped portion 160 to the inner diameter IS of the spring 50is between 0.901 and 0.98.

In one example, the outer diameter Dc of the cup-shaped portion 160 is0.439 inches (1.115 centimeters) and the length L_(S) of the cup-shapedportion 160 is 0.092 inches (0.234 centimeters). The ratio of outerdiameter Dc of the cup-shaped portion 160 to the length L_(S) of thecup-shaped portion 160 is between 4.0 and 5.0.

The spring assembly 48 serves to remove side-loading from the HPRV 30.The seat 52 is sized to hold the ball 54, with the seat walls beingsized to handle the spring loads and ball contact stress. The disc outerdiameter OD is sized to align with the piston inner diameter IDP, whichreduces shucking of the seat assembly. The disc inner diameter ID issized for the ball size and to accommodate contact stresses. The discthickness T is sized to ensure that the ball 54 never contacts thepiston 44. The ball 54 is sized to fit into the seat 52 while optimizingpivoting and minimizing contact stresses. In one example, the assemblyis configured to allow for approximately 8 degrees of rotation.

In a method of replacing a piston 44, nozzle 46, spring assembly 48, orclosure sleeve 42 in a HPRV 30, at least one of the piston 44, nozzle46, spring assembly 48 or closure sleeve 42 is removed from the valvehousing 40, and at least one of a replacement piston, nozzle, springassembly, or closure sleeve replaces the removed piston, nozzle, springassembly, or closure sleeve. The piston, nozzle, spring assembly, orclosure sleeve which is replaced is generally as disclosed above.

With a valve made according to the above description, the pressurelosses across the valve are dramatically reduced and the operating isimproved when compared to the prior art.

Although an embodiment of this invention has been disclosed, a worker ofordinary skill in this art would recognize that certain modificationswould come within the scope of this invention. For that reason, thefollowing claims should be studied to determine the true scope andcontent of this invention.

The invention claimed is:
 1. A spring assembly for a valve comprising: aspring; a spring seat including a cup-shaped portion for seating one endof the spring; a ball received within a recess formed within thecup-shaped portion of the spring seat, wherein the ball is defined by aball diameter, and wherein the spring seat is rotatable about the ball;and a disc that prevents the ball from contacting a piston, wherein thedisc is defined by an outer diameter and includes a center openingdefined by an inner diameter, and wherein a ratio of the inner diameterto the ball diameter is between 0.60 and 0.65.
 2. The spring assemblyaccording to claim 1, wherein the disc is defined by a thicknessextending from an upstream side of the disc to a downstream side of thedisc, and wherein a ratio of the thickness of the disc to the outerdiameter of the disc is between 0.06 and 0.08.
 3. The spring assemblyaccording to claim 1, wherein the recess of the cup-shaped portion isdefined by a recess inner diameter and wherein a ratio of the recessinner diameter to the ball diameter is between 1.01 and 1.10.
 4. Thespring assembly according to claim 1, wherein the cup-shaped portion isdefined by an outer diameter and by a length, and wherein a ratio of theouter diameter of the cup-shaped portion to the length of the cup-shapedportion is between 4 and
 5. 5. A spring assembly for a valve comprising:a spring defined by an inner diameter; a spring seat including acup-shaped portion for seating one end of the spring, wherein thecup-shaped portion is defined by an outer diameter; a ball receivedwithin a recess formed within the cup-shaped portion of the spring seat,and wherein the spring seat is rotatable about the ball; and a disc thatprevents the ball from contacting a piston, and wherein a ratio of theouter diameter of the cup-shaped portion to the inner diameter of thespring is between 0.90 and 0.98.
 6. A spring and piston assembly for avalve comprising: a piston having an outer surface defined by a maximumouter diameter, the outer surface being configured for engagement with avalve closure sleeve, and wherein the piston includes a piston boredefined by a piston inner diameter; a spring assembly positioned withinthe piston bore, the spring assembly including a spring, a spring seatincluding a cup-shaped portion for seating one end of the spring, a ballreceived within a recess formed within the cup-shaped portion of thespring seat, wherein the spring seat is rotatable about the ball; and adisc that prevents the ball from contacting a piston, wherein the discis defined by an outer diameter, and wherein a ratio of the outerdiameter of the disc to the piston inner diameter is between 0.97 and0.99.
 7. The spring and piston assembly according claim 6, wherein thespring seat is defined by a maximum outer diameter and wherein a ratioof the maximum outer diameter of the spring seat to the piston innerdiameter is between 0.8 and 0.9.
 8. A high pressure relief valvecomprising: a valve housing defining an internal bore and having a valveinlet configured to be in fluid communication with a pump outlet; aclosure sleeve at least partially received within the internal bore, theclosure sleeve comprising a sleeve body surrounding a center axis,wherein the sleeve body has an internal cavity that is enclosed at thedownstream end and open at the upstream end; a piston received withinthe internal cavity, wherein the internal cavity is defined in part by apiston contact surface that is defined by an inner diameter, and whereinthe piston includes an outer surface defined by a maximum outer pistondiameter and a piston bore that is defined by a piston inner diameter,wherein the piston contact surface slides against the outer surface ofthe piston; a nozzle received within the internal bore of the valvehousing and including a nozzle bore having a nozzle inlet in fluidcommunication with the valve inlet and a nozzle outlet; a springassembly that biases the piston to close the nozzle outlet, wherein thespring assembly includes a spring, a spring seat including a cup-shapedportion for seating one end of the spring, a ball received within arecess formed within the cup-shaped portion of the spring seat, and adisc that prevents the ball from contacting a piston, and wherein when asystem pressure at the nozzle outlet exceeds a predetermined pressurelevel, a spring biasing load is overcome to open the nozzle outlet tofluidly connect the nozzle to the internal cavity of the closure sleeve;and wherein the high pressure relief valve includes one or more of thefollowing valve characteristics wherein the ball is defined by a balldiameter and wherein the disc is defined by an outer diameter andincludes a center opening defined by an inner diameter, and wherein aratio of the inner diameter to the ball diameter is between 0.60 and0.65, wherein the disc is defined by a thickness extending from anupstream side of the disc to a downstream side of the disc, and whereina ratio of the thickness of the disc to the outer diameter of the discis between 0.06 and 0.08, wherein the recess formed within thecup-shaped portion of the spring seat is defined by a recess innerdiameter and wherein a ratio of the recess inner diameter to the balldiameter is between 1.01 and 1.10, wherein the spring is defined by aninner diameter, and wherein the cup-shaped portion is defined by anouter diameter, and wherein a ratio of the outer diameter of thecup-shaped portion to the inner diameter of the spring is between 0.90and 0.98, wherein the cup-shaped portion is defined by an outer diameterand by a length, and wherein a ratio of the outer diameter of thecup-shaped portion to the length of the cup-shaped portion is between 4and 5, wherein the disc is defined by an outer diameter, and wherein aratio of the outer diameter of the disc to the piston inner diameter isbetween 0.97 and 0.99, wherein the spring seat is defined by a maximumouter diameter, and wherein a ratio of the maximum outer diameter of thespring seat to the piston inner diameter is between 0.8 and 0.9.
 9. Afuel supply system incorporating: a fuel pump having a pump inlet and apump outlet, the pump inlet being in fluid communication with a fuelsupply; a metering valve receiving fuel from the fuel pump and directingthe fuel to a gas turbine engine; and a high pressure relief valveupstream of the metering valve and downstream of the pump inlet, thehigh pressure relief valve being configured to move to an open positiononce system pressure downstream of the pump outlet exceeds apredetermined pressure level such the fuel can be returned to the pumpinlet via the high pressure relief valve, and wherein the high pressurerelief valve comprises a valve housing defining an internal bore andhaving a valve inlet configured to be in fluid communication with a pumpoutlet; a closure sleeve at least partially received within the internalbore, the closure sleeve comprising a sleeve body surrounding a centeraxis, wherein the sleeve body has an internal cavity that is enclosed atthe downstream end and open at the upstream end; a piston receivedwithin the internal cavity, wherein the internal cavity is defined inpart by a piston contact surface that is defined by an inner diameter,and wherein the piston includes an outer surface defined by a maximumouter piston diameter and a piston bore that is defined by a pistoninner diameter, wherein the piston contact surface slides against theouter surface of the piston; a nozzle received within the internal boreof the valve housing and including a nozzle bore having a nozzle inletin fluid communication with the valve inlet and a nozzle outlet; aspring assembly that biases the piston to close the nozzle outlet,wherein the spring assembly includes a spring, a spring seat including acup-shaped portion for seating one end of the spring, a ball receivedwithin a recess formed within the cup-shaped portion of the spring seat,and a disc that prevents the ball from contacting a piston, and whereinwhen a system pressure at the nozzle outlet exceeds a predeterminedpressure level, a spring biasing load is overcome to open the nozzleoutlet to fluidly connect the nozzle to the internal cavity of theclosure sleeve; and wherein the high pressure relief valve includes oneor more of the following valve characteristics wherein the ball isdefined by a ball diameter and wherein the disc is defined by an outerdiameter and includes a center opening defined by an inner diameter, andwherein a ratio of the inner diameter to the ball diameter is between0.60 and 0.65, wherein the disc is defined by a thickness extending froman upstream side of the disc to a downstream side of the disc, andwherein a ratio of the thickness of the disc to the outer diameter ofthe disc is between 0.06 and 0.08, wherein the recess formed within thecup-shaped portion of the spring seat is defined by a recess innerdiameter and wherein a ratio of the recess inner diameter to the balldiameter is between 1.01 and 1.100, wherein the spring is defined by aninner diameter, and wherein the cup-shaped portion is defined by anouter diameter, and wherein a ratio of the outer diameter of thecup-shaped portion to the inner diameter of the spring is between 0.90and 0.98, wherein the cup-shaped portion is defined by an outer diameterand by a length, and wherein a ratio of the outer diameter of thecup-shaped portion to the length of the cup-shaped portion is between 4and 5, wherein the disc is defined by an outer diameter, and wherein aratio of the outer diameter of the disc to the piston inner diameter isbetween 0.97 and 0.99, wherein the spring seat is defined by a maximumouter diameter, and wherein a ratio of the maximum outer diameter of thespring seat to the piston inner diameter is between 0.8 and 0.9.
 10. Thespring assembly according to claim 1, wherein the ball axially spacesthe spring seat apart from the disc by a gap to allow rotation of thespring seat relative to the disc.
 11. The spring assembly according toclaim 10, wherein the ball allows the spring seat to rotate around theball by approximately eight degrees.
 12. The spring assembly accordingto claim 10, wherein the spring seat includes an enlarged flange portionwith an outer edge that defines a maximum outer diameter of the springseat, and wherein the outer edge contacts the disc to define a pivotstop.
 13. The spring assembly according to claim 5, wherein the ballaxially spaces the spring seat apart from the disc by a gap to allowrotation of the spring seat relative to the disc.
 14. The springassembly according to claim 13, wherein the ball allows the spring seatto rotate around the ball by approximately eight degrees.
 15. The springassembly according to claim 13, wherein the spring seat includes anenlarged flange portion with an outer edge that defines a maximum outerdiameter of the spring seat, and wherein the outer edge contacts thedisc to define a pivot stop.
 16. The spring and piston assemblyaccording to claim 6, wherein the ball axially spaces the spring seatapart from the disc by a gap to allow rotation of the spring seatrelative to the disc.
 17. The spring and piston assembly according toclaim 16, wherein the ball allows said spring seat to rotate around theball by approximately eight degrees.
 18. The spring and piston assemblyaccording to claim 16, wherein the spring seat includes an enlargedflange portion with an outer edge that defines a maximum outer diameterof the spring seat, and wherein the outer edge contacts the disc todefine a pivot stop.
 19. The spring and piston assembly according toclaim 18, wherein the outer edge slides along an inner surface of thepiston bore.